I. Field of the Invention
The present invention is directed generally to refrigeration systems, particularly to those of the vapor compression variety exemplified by so-called "split" systems which are well known and includes separate compartments for cooling and heat dissipation. The cooling or refrigeration compartment is a closed system that includes an evaporator which absorbs heat from and cools the surrounding air and the heat dissipating compartment is open and houses a compressor, together with an air cooled condenser unit, typically a fin and tube heat exchange device. More specifically, the present invention deals with the provision of a protective air filter arrangement for the condenser unit associated with the compressor that prevents dirt buildup on heat transfer surfaces without unduly restricting cooling air flow.
II. Related Art
High duty refrigeration systems such as those utilized in conjunction with packaged ice merchandizing or vending storage chests, or indoor ice making and dispensing machines such as those found in hotels, require the dissipation of relatively large amounts of heat at the condenser during operation. This requires large amounts of cooling air to be utilized to cool the condenser to maintain the temperature of the condenser at or less than the desired maximum operating temperature. The well-known coil and high surface fin heat transfer heat exchange devices used for such systems may be open and totally unprotected, but more often are enclosed in a metal box structure provided with a series of louvered slots or openings through which air is admitted and discharged. Air flow is maintained by a shroud enclosed cooling fan which pulls ambient air in through the louvers and over the closely spaced fins and discharges it from the opposite side of the structure. While this generally assures an adequate supply of cooling air for the condenser, dust and other foreign airborne materials and debris in the ambient air are also sucked through the system. These tend to accumulate on the heat transfer surfaces of the system and are difficult to clean particularly in view of the close parallel spacing of the fin surfaces. In some instances, complete clogging between some of the fins may occur. Contaminates on the cooling surfaces, of course, tend to reduce heat transfer efficiency and may result in the condenser operating at a higher than ideal temperature thereby reducing overall system efficiency. This also, of course, requires the compressor to operate less efficiently and for more of the time than designed each cycle and may lead to premature compressor failure.
The problem is particularly severe with regard to self-contained ice making machines and packaged ice storage chests such as those located inside convenience stores, or the like, where the condenser is exposed to a dusty environment. Dust, lint and other airborne debris are known to accumulate indoors and this problem has worsened more recently because energy efficiency concerns with regard to heating and cooling have led people to reduce air leakage and ventilation. Also, because of factors such as theft and vandalism, many units, formerly outdoors have simply been moved indoors to avoid crime problems. In some instances, where clogging or dust buildup may not have been much of a concern outdoors, problems occurred when the system was moved inside. Units located outside buildings are more susceptible to buildup of dust where unpaved parking or other dust sources are nearby. Presently, nothing is provided to prevent or reduce natural buildup and contamination of the cooling surfaces from dust and airborne debris.
In most applications, the heat transfer fins are hard to access for cleaning and difficult to clean without special tools and sources of high pressure air or water to blast accumulated debris from the surfaces. On the other hand, failure to clean the system on a regular basis may lead to higher inefficiency and shorter compressor life as indicated above.
Accordingly, it is a primary object of the present invention to provide a low cost inlet filter system to reduce contamination of the heat transfer surfaces of a refrigerant condenser system utilizing ambient cooling air.
Another object of the present invention is to provide a low cost cooling air inlet filter for a condenser unit that uses a replaceable filter element.
Yet another object of the present invention is to provide an inlet filter system that minimizes associated flow restriction and refrigerant temperature rise in the condenser unit.
Yet still another object of the present invention is to provide a cooling air filter system that includes a replaceable filter element and signaling device to indicate that the element needs changing.
Other objects and advantages of the present invention will occur to those skilled in the art upon further familiarization with the specification, drawings and claims contained herein.